Wool is one of the most important animal fibres used in textile manufacture. Wool is considered superior to other fibres because of its outstanding natural properties of feel, moisture absorption, strength and its ability to hang. Before wool can be used in textile manufacture or for other uses, it must undergo a number of treatment processes.
Raw wool from sheep and other animals contains many constituents considered contaminants by wool processors and the contaminants must be substantially removed from the wool prior to use. The type and amount of contaminants can vary according to breed, nutrition, environment and position of the wool on the animal. The main contaminants are a solvent-soluble fraction called wool grease, protein material, a water-soluble fraction (largely perspiration salts collectively termed suint), dirt and vegetable matter in the form of burrs and seeds from pastures. A fleece may contain up to 30% by weight of contaminants, depending on the animal, so it is important that the wool is treated before use.
The first process of preparing wool involves the removal of the contaminants and this process is termed scouring.
In traditional wool scouring, the contaminants on the wool, mainly grease, dirt, suint and protein material are washed from the wool fibre using water and detergents. The contaminants remain in the waste water either in emulsion or suspension (grease, dirt, protein) or in solution (suint). Extraction of the waste water produces grease contaminated with detergent and suint and is termed wool grease. The traditional methods of wool scouring involve extensive processing, the addition of detergents, and the use of large amounts of water. Typical scouring plants can consume up to half a million litres of water per day. Apart from the requirement of a large amount of water, there is a problem of disposing of the waste water without unduly contaminating the environment. The problem of disposal involves further expense and, with stricter environmental emission controls, requires some form of treatment prior to release into the environment.
Other contaminants present in raw wool include herbicides and pesticides which often require specific treatment to remove them from waste water produced in conventional scouring. Any increased costs of scouring wool are usually passed on to the consumer and therefore result in an increase in the price of wool in relation to other competing fibres, including man-made fibres, used in the same industries.
The present inventor has developed a method for scouring wool that requires substantially less water consumption than present methods and involves an efficient means of producing clean wool.